The invention is in the field of inverter circuits employing transistors as switches for producing a-c output energy from d-c input energy.
Inverter circuits have been known in various configurations, such as push-pull, full-bridge, and half-bridge. A widely used type of push-pull inverter circuit employs a center-tapped load often in the form of a transformer having a center-tapped primary winding, and a secondary winding connected to a load device such as a lamp or lamps, for example fluorescent lamps, or a motor, induction heater, or other suitable device. A pair of transistor switches are respectively connected to the ends of the primary winding and are controlled to switch current through the halves of the primary winding in an alternating push-pull manner.
The above-referenced patent applications, the disclosures of which are incorporated herein by reference thereto, disclose inverter circuits in which the switching transistors are alternately rendered conductive by stored charges produced therein by flyback induced voltage in the load. FIG. 5 of the second referenced patent application discloses a push-pull stored charge inverter circuit having two individual control circuits for synchronously controlling the switching of the switching transistors.